Skateboard with safer turning

ABSTRACT

A skateboard comprises a board, front and rear wheel bases respectively mounted to front and rear portions of an underside of the board, and front and rear axles respectively attached to the front and rear wheel bases. The front axle has a portion abutting against the front wheel base such that the front axle pivots toward a loading point when a load is applied to the loading point not locating on a central longitudinal axis of the skateboard. The rear axle has a portion abutting against the rear wheel base such that the rear axle pivots toward a loading point when a load is applied to the loading point not locating on the central longitudinal axis of the skateboard.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a skateboard that provides an improved cushioning effect, prevents falling of the skater during turning, and provides an easier, safer turning.

[0003] 2. Description of the Related Art

[0004]FIG. 1 of the drawings illustrates a conventional skateboard comprising a board 10 to which two wheel bases 11 are mounted. Each wheel base 11 comprises an inclined hole 12. An axle 13 comprises two ends to which two wheels 14 are mounted. The axle 13 comprises a bulged portion with a hole 131. A cushioning member 15 is mounted between the inclined hole 12 and the hole 131. A bolt 16 is extended through the inclined hole 12 of the wheel seat 11, the cushioning member 15, hole 131 of the axle 13, and a washer 17, and then engaged with a nut 18. A peg 132 extends from the axle 13 into a hole 121 in the wheel seat 11. When running over a rugged surface, it was found that the cushioning effect provided by the cushioning member 15 was poor. In addition, when the skateboard is turning, the inner wheels are apt to wear due to friction resulting from concentrated load during turning. Further, the outer wheels may leave the ground and thus causes a hazard situation, as the skateboard is supported by two inner wheels located along a line.

SUMMARY OF THE INVENTION

[0005] An object of the present invention is to provide a skateboard that provides an improved cushioning effect, prevents falling of the skater during turning, and provides an easier, safer turning.

[0006] In accordance with a first aspect of the invention, a skateboard comprises:

[0007] a board including an underside having a front portion and a rear portion;

[0008] a front wheel base securely attached to the front portion of the underside of the board, the front wheel base comprising an underside having an abutting portion;

[0009] a front axle attached to the front wheel base, the front axle having a portion abutting against the abutting portion of the front wheel base such that the front axle pivots toward a loading point when a load is applied to the loading point not locating on a central longitudinal axis of the skateboard;

[0010] two front wheels rotatably attached to two ends of the front axle;

[0011] a rear wheel base securely attached to the rear portion of the underside of the board, the rear wheel base comprising an underside having an abutting portion;

[0012] a rear axle attached to the rear wheel base, the rear axle having a portion abutting against the abutting portion of the rear wheel base such that the rear axle pivots toward a loading point when a load is applied to the loading point not locating on the central longitudinal axis of the skateboard; and

[0013] two rear wheels rotatably attached to two ends of the rear axle.

[0014] In accordance with a second aspect of the invention, a skateboard comprises:

[0015] a board including an underside having a front portion and a rear portion;

[0016] a front wheel base securely attached to the front portion of the underside of the board, the front wheel base including an underside having a left portion and a right portion;

[0017] a front axle attached to the underside of the front wheel base, the front axle having a left portion and a right portion;

[0018] a first spring attached between the left portion of the underside of the front wheel base and the left portion of the front axle;

[0019] a second spring attached between the right portion of the underside of the front wheel base and the right portion of the front axle;

[0020] two front wheels rotatably attached to two ends of the front axle;

[0021] a rear wheel base securely attached to the rear portion of the underside of the board, the rear wheel base comprising an underside having a left portion and a right portion;

[0022] a rear axle attached to the underside of the rear wheel base, the rear axle having a left portion and a right portion;

[0023] a third spring attached between the left portion of the underside of the rear wheel base and the left portion of the rear axle;

[0024] a fourth spring attached between the right portion of the underside of the rear wheel base and the right portion of the rear axle; and

[0025] two rear wheels rotatably attached to two ends of the rear axle.

[0026] Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is an exploded perspective view of a portion of a conventional skateboard.

[0028]FIG. 2 is a perspective view of a skateboard in accordance with the present invention.

[0029]FIG. 3 is a perspective view of a wheel base, an axle, and two wheels of the skateboard in accordance with the present invention.

[0030]FIG. 4 is an exploded perspective view of the wheel base, the axle, and the wheels in FIG. 3.

[0031]FIG. 5 is a side view of the skateboard in accordance with the present invention.

[0032]FIG. 6 is a sectional view taken along plane A-A in FIG. 2.

[0033]FIG. 7 is a view similar to FIG. 6, illustrating turning in a direction of the skateboard in accordance with the present invention.

[0034]FIG. 8 is a top view illustrating turning in a direction of the skateboard in accordance with the present invention.

[0035]FIG. 9 is a sectional view similar to FIG. 7, illustrating turning in another direction of the skateboard in accordance with the present invention.

[0036]FIG. 10 is a top view illustrating turning in another direction of the skateboard in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0037] Referring to FIGS. 2 through 5, a skateboard in accordance with the present invention generally comprises a board 20, a front wheel base 21, a rear wheel base 21, and a left cushioning device 40 and a right cushioning device 50 for each wheel base 21. The front wheel base 21 comprises an upper side 211 securely attached to a front portion of an underside of the board 20, an underside 212, a first end wall 213 facing a front of the board 20, and a second end wall 214 facing a rear of the board 20. A receiving groove or space 26 is defined in the underside 212 of the front wheel base 21. In this embodiment, a mounting portion 22 is formed on an end of the underside 212 of the front wheel base 21 and has a side 28 that delimits the receiving space 26. Two sockets 221 are defined in the side 28 of the mounting portion 22 and respectively located on left and right portions of the side 28 of the mounting portion 22. A peg 222 is formed on a bottom wall defining each socket 221. It is noted that one of the sockets 221 extends along a first axis at an angle with a vertical axis, and the other socket 221 extends along a second axis at an angle with the vertical axis, the first axis and the second axis being intersecting with each other. Preferably, the first axis and the second axis intersect with each other at a point located on the vertical axis.

[0038] In this embodiment, an abutting portion 23 is formed on the other end of the underside 212 of the front wheel base 21. The abutting portion 23 includes a first side 233 that delimits the receiving space 26 and a second side that forms the second end wall 214 of the front wheel base 21. An inclined hole 231 extends from the second side 214 through the first side 233 of the abutting portion 23 and is contiguous to a notch 232 that is defined in the second side 214 of the front wheel base 21.

[0039] A front axle 30 comprises two ends to which two wheels 31 are rotatably attached. The front axle 30 further comprises two sidewalls in an intermediate portion thereof, thereby defining a groove 32 between the sidewalls. A transverse hole 322 extends through the sidewalls. One of the sidewalls has an outer face 321. Two pegs 323 are formed on a left portion and a right portion of a bottom wall defining the groove 32. One of the pegs 323 extends along the first axis at an angle with the vertical axis, and the other peg 323 extends along the second axis at an angle with the vertical axis, as mentioned above. Namely, each of the pegs 323 aligns with an associated one of the pegs 222 of the front wheel base 21.

[0040] Each of the first cushioning device 40 and the second cushioning device 50 comprises an upper sleeve 42, 52, a spring 41, 51, and a lower spring 42, 52. Each upper sleeve 42, 52 includes a first end 421, 521 having a receptacle 424, 524 for receiving an associated peg 222 of the front wheel base 21. Each lower sleeve 42, 52 includes a first end 421, 521 having a receptacle 424, 524 for receiving an associated peg 323 of the front axle 30. A peg 423, 523 is provided in a second end 422, 522 of each upper sleeve 42, 52, and a peg 423, 523 is provided in a second end 422, 522 of each lower sleeve 42, 52. The spring 42, 52 has an upper end 411, 511 securely attached to an associated peg 423, 523 of the upper sleeve 42, 52 and a lower end 412, 512 securely attached to an associated peg 423, 523 of the lower sleeve 42, 52.

[0041] The outer face 321 of the front axle 30 abuts against the first side 233 of the abutting portion 23 of the front wheel base 21. A fastener such as a bolt 43 extends through the inclined hole 231 and the transverse hole 322, and a nut 44 is engaged with the bolt 43. Thus, the front axle 30 is pivotally attached to the front wheel base 21 such that the front axle 30 may pivot relative to the front wheel base 21.

[0042] The rear wheel base 21 is mounted to a rear portion of the underside 212 of the board 20 and has a structure identical to that of the front wheel base 21 except for the facing direction of the end walls after assembly. Namely, the first end wall 213 of the rear wheel base 21 faces the rear of the board 20 and the second end wall 214 of the rear wheel base 21 faces the front of the board 20, best shown in FIG. 5. A rear axle 30 having a structure identical to that of the rear axle 30 is mounted to the rear wheel base 21 in a manner symmetrical to assembly of the front axle 30 and the front wheel base 21. Further, the assembly of the first and second cushioning devices 40 and 50, the rear axle 30, and the rear wheel base 21 are identical to that of the first and second cushioning devices 40 and 50, the front axle 30, and the front wheel base 21.

[0043] Referring to FIG. 6, when a skater stands on the board 20, the load is distributed to the front and rear cushioning devices 40 and 50 attached to the front and rear wheel bases 21. The cushioning devices 40 and 50 provide a cushioning effect while running through a rugged surface.

[0044] Referring to FIGS. 7 and 8, when the skater intends to turn, e.g., leftward during skating, the skater shifts his center of gravity leftward while standing on the board 20. As illustrated in FIG. 7, the first cushioning device 40 between the front wheel base 21 and the front axle 30 and the first cushioning device 40 between the rear wheel base 21 and the rear axle 30 are compressed. Namely, each wheel base 21 is supported by the associated first cushioning device 40 only. An advantage of this design is that the outer wheels 31 of the skateboard stay on the ground during turning and thus provide a stable turning, best shown in FIG. 7. In addition, the shifting of the center of gravity of the skater on the board 20 causes shifting of the load. Namely, the load during turning concentrates on an inner portion of the board 20 with respect to the turning direction. Since the first side 233 of the abutting portion 23 of each wheel base 21 abuts against the outer face 321 of each axle 30, when the skateboard turns as a result of shifting of the center of gravity of the skater, the front axle 30 and the rear axle 30 pivot in opposite directions such that a longitudinal axis N₁ of the front axle 30 intersects a longitudinal axis N₂ of the rear axle 30 at a point O, which forms the center of curvature during turning, best shown in FIG. 8. The distance R (i.e., the radius of turn) between the point O and the inner front wheel 31 is the same as that between the point O and the inner rear wheel 31. This allows a smooth, easy, and safe turning.

[0045] Referring to FIGS. 9 and 10, when the skater intends to turn, e.g., rightward during skating, the skater shifts his center of gravity rightward while standing on the board 20. As illustrated in FIG. 9, the second cushioning device 50 between the front wheel base 21 and the front axle 30 and the second cushioning device 50 between the rear wheel base 21 and the rear axle 30 are compressed. Namely, each wheel base 21 is supported by the associated second cushioning device 50 only. An advantage of this design is that the inner wheels 31 of the skateboard stay on the ground during turning and thus provide a stable turning, best shown in FIG. 9. In addition, the shifting of the center of gravity of the skater on the board 20 causes shifting of the load. Namely, the load during turning concentrates on an inner portion of the board 20 with respect to the turning direction. Since the first side 233 of the abutting portion 23 of each wheel base 21 abuts against the outer face 321 of each axle 30, when the skateboard turns as a result of shifting of the center of gravity of the skater, the front axle 30 and the rear axle 30 pivot in opposite directions such that the longitudinal axis N₁ of the front axle 30 intersects the longitudinal axis N₂ of the rear axle 30 at a point O′, which forms the center of curvature during turning, best shown in FIG. 8. The distance R′ (i.e., the radius of turn) between the point O′ and the inner front wheel 31 is the same as that between the point O′ and the inner rear wheel 31. This allows a smooth, easy, and turning.

[0046] According to the above description, it is appreciated that the skateboard in accordance with the present invention allows smooth, stable turning while providing the desired cushioning effect. In addition, the radius of the skateboard in accordance with the present invention is smaller than that of conventional skateboards. This is owing to the feature that the front axle 30 pivots toward the loading point relative to the front wheel base 21 and the rear axle 30 pivots toward a loading point relative to the rear wheel base 21 when the load is applied to the loading point not locating on a central longitudinal axis of the board 20.

[0047] Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the invention as hereinafter claimed. 

What is claimed is:
 1. A skateboard comprising: a board including an underside having a front portion and a rear portion; a front wheel base securely attached to the front portion of the underside of the board, the front wheel base comprising an underside having an abutting portion; a front axle attached to the front wheel base, the front axle having a portion abutting against the abutting portion of the front wheel base such that the front axle pivots toward a loading point when a load is applied to the loading point not locating on a central longitudinal axis of the skateboard; two front wheels rotatably attached to two ends of the front axle; a rear wheel base securely attached to the rear portion of the underside of the board, the rear wheel base comprising an underside having an abutting portion; a rear axle attached to the rear wheel base, the rear axle having a portion abutting against the abutting portion of the rear wheel base such that the rear axle pivots toward a loading point when a load is applied to the loading point not locating on the central longitudinal axis of the skateboard; and two rear wheels rotatably attached to two ends of the rear axle.
 2. The skateboard as claimed in claim 1, wherein the underside of the front wheel base comprises a left portion and a right portion, the front axle having a left portion and a right portion, further comprising a first spring attached between the left portion of the front wheel base and the left portion of the front axle, and a second spring attached between the right portion of the front wheel base and the right portion of the front axle.
 3. The skateboard as claimed in claim 1, wherein the underside of the rear wheel base comprises a left portion and a right portion, the rear axle having a left portion and a right portion, further comprising a first spring attached between the left portion of the rear wheel base and the left portion of the rear axle, and a second spring attached between the right portion of the rear wheel base and the right portion of the rear axle.
 4. The skateboard as claimed in claim 2, wherein the underside of the rear wheel base comprises a left portion and a right portion, the rear axle having a left portion and a right portion, further comprising a third spring attached between the left portion of the rear wheel base and the left portion of the rear axle, and a fourth spring attached between the right portion of the rear wheel base and the right portion of the rear axle.
 5. The skateboard as claimed in claim 4, wherein the underside of the front wheel base comprises a receiving space, a side defining the receiving space comprising a first socket and a second socket, the first socket receiving an end of the first spring, the second socket receiving an end of the second spring.
 6. The skateboard as claimed in claim 5, wherein the front axle comprising a groove delimited by two sidewalls and a bottom wall, a first peg and a second peg being provided on a left portion and a right portion of the bottom wall defining the groove, further comprising: a first upper sleeve mounted between an end of the first spring and an end wall defining the first socket; a first lower sleeve mounted between another end of the first spring and the first peg; a second upper sleeve mounted between an end of the second spring and an end wall defining the second socket; and a second lower sleeve mounted between another end of the second spring and the second peg.
 7. The skateboard as claimed in claim 6, wherein the end wall defining the first socket comprises a peg and wherein the first upper sleeve comprises a receptacle in an end thereof for receiving the peg in the first socket.
 8. The skateboard as claimed in claim 7, wherein the first lower sleeve comprises a receptacle in an end thereof for receiving the first peg.
 9. The skateboard as claimed in claim 6, wherein the end wall defining the second socket comprises a peg and wherein the second upper sleeve comprises a receptacle in an end thereof for receiving the peg in the second socket.
 10. The skateboard as claimed in claim 9, wherein the second lower sleeve comprises a receptacle in an end thereof for receiving the second peg.
 11. The skateboard as claimed in claim 7, wherein the first socket extending along a first axis at an angle with a vertical axis, the second socket extending along a second axis at an angle with the vertical axis, the first axis and the second axis intersecting with each other at a point on the vertical axis.
 12. The skateboard as claimed in claim 5, wherein the rear axle comprising a groove delimited by two sidewalls and a bottom wall, a first peg and a second peg being provided on a left portion and a right portion of the bottom wall defining the groove, further comprising: a first upper sleeve mounted between an end of the first spring and an end wall defining the first socket; a first lower sleeve mounted between another end of the first spring and the first peg; a second upper sleeve mounted between an end of the second spring and an end wall defining the second socket; and a second lower sleeve mounted between another end of the second spring and the second peg.
 13. The skateboard as claimed in claim 12, wherein the end wall defining the first socket comprises a peg and wherein the first upper sleeve comprises a receptacle in an end thereof for receiving the peg in the first socket.
 14. The skateboard as claimed in claim 13, wherein the first lower sleeve comprises a receptacle in an end thereof for receiving the first peg.
 15. The skateboard as claimed in claim 12, wherein the end wall defining the second socket comprises a peg and wherein the second upper sleeve comprises a receptacle in an end thereof for receiving the peg in the second socket.
 16. The skateboard as claimed in claim 15, wherein the second lower sleeve comprises a receptacle in an end thereof for receiving the second peg.
 17. The skateboard as claimed in claim 13, wherein the first socket extending along a first axis at an angle with a vertical axis, the second socket extending along a second axis at an angle with the vertical axis, the first axis and the second axis intersecting with each other at a point on the vertical axis.
 18. A skateboard comprising: a board including an underside having a front portion and a rear portion; a front wheel base securely attached to the front portion of the underside of the board, the front wheel base including an underside having a left portion and a right portion; a front axle attached to the underside of the front wheel base, the front axle having a left portion and a right portion; a first spring attached between the left portion of the underside of the front wheel base and the left portion of the front axle; a second spring attached between the right portion of the underside of the front wheel base and the right portion of the front axle; two front wheels rotatably attached to two ends of the front axle; a rear wheel base securely attached to the rear portion of the underside of the board, the rear wheel base comprising an underside having a left portion and a right portion; a rear axle attached to the underside of the rear wheel base, the rear axle having a left portion and a right portion; a third spring attached between the left portion of the underside of the rear wheel base and the left portion of the rear axle; a fourth spring attached between the right portion of the underside of the rear wheel base and the right portion of the rear axle; and two rear wheels rotatably attached to two ends of the rear axle. 